Mark, thanks for the caution about the impeller vs. HP possibility. I checked that on the Sta-Rite Max-E-Pro line and there were both different impellers and different motors with different current draws for their 1/2 and 3/4 HP models.

I also appreciate the dynamic head loss vs. HP equation. I presumed there had to be some kind of change with HP since the term is "dynamic" after all!